diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 3a1444d..509c0ee 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -16146,6 +16146,20 @@ ix86_fp_compare_code_to_integer (enum rtx_code code)
     }
 }
 
+/* Override compare_by_pieces' default implementation using the state
+   of the CCZmode FLAGS_REG and sete instruction.  TARGET is the integral
+   mode result, and FAIL_LABEL is the branch target of mismatched
+   comparisons.  */
+
+void
+ix86_finish_compare_by_pieces (rtx target, rtx_code_label *fail_label)
+{
+  rtx tmp = gen_reg_rtx (QImode);
+  emit_label (fail_label);
+  ix86_expand_setcc (tmp, NE, gen_rtx_REG (CCZmode, FLAGS_REG), const0_rtx);
+  convert_move (target, tmp, 1);
+}
+
 /* Zero extend possibly SImode EXP to Pmode register.  */
 rtx
 ix86_zero_extend_to_Pmode (rtx exp)
@@ -25127,6 +25141,8 @@ ix86_run_selftests (void)
 
 #undef TARGET_OVERLAP_OP_BY_PIECES_P
 #define TARGET_OVERLAP_OP_BY_PIECES_P hook_bool_void_true
+#undef TARGET_FINISH_COMPARE_BY_PIECES
+#define TARGET_FINISH_COMPARE_BY_PIECES ix86_finish_compare_by_pieces
 
 #undef TARGET_FLAGS_REGNUM
 #define TARGET_FLAGS_REGNUM FLAGS_REG
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 95ba56e..28d8361 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -6922,6 +6922,18 @@ particular mode from being used for block comparisons by returning a
 negative number from this hook.
 @end deftypefn
 
+@deftypefn {Target Hook} void TARGET_FINISH_COMPARE_BY_PIECES (rtx @var{target}, rtx_code_label *@var{fail_label})
+Allow targets with a zero flag and suitable setcc instruction to provide
+an alternate implementation for @code{compare_by_pieces}.  The function
+@code{compare_by_pieces} generates a sequence of equality tests that
+branch to @var{failure_label} on mismatches, and fall through on success.
+By default, this hook assigns @code{const1_rtx} to @var{target} in the
+current basic block and @code{const0_rtx} to @var{target} in a new
+@var{fail_label} basic block.  Targets like x86 can take advantage
+of the property that the condition codes/zero flag are appropriately
+set to avoid introducing a new basic block.
+@end deftypefn
+
 @defmac MOVE_MAX_PIECES
 A C expression used by @code{move_by_pieces} to determine the largest unit
 a load or store used to copy memory is.  Defaults to @code{MOVE_MAX}.
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 4ac96dc..45711db 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -4529,6 +4529,8 @@ If you don't define this, a reasonable default is used.
 
 @hook TARGET_COMPARE_BY_PIECES_BRANCH_RATIO
 
+@hook TARGET_FINISH_COMPARE_BY_PIECES
+
 @defmac MOVE_MAX_PIECES
 A C expression used by @code{move_by_pieces} to determine the largest unit
 a load or store used to copy memory is.  Defaults to @code{MOVE_MAX}.
diff --git a/gcc/expr.cc b/gcc/expr.cc
index 868fa6e..25fca17 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -1923,7 +1923,6 @@ compare_by_pieces (rtx arg0, rtx arg1, unsigned HOST_WIDE_INT len,
 		   by_pieces_constfn a1_cfn, void *a1_cfn_data)
 {
   rtx_code_label *fail_label = gen_label_rtx ();
-  rtx_code_label *end_label = gen_label_rtx ();
 
   if (target == NULL_RTX
       || !REG_P (target) || REGNO (target) < FIRST_PSEUDO_REGISTER)
@@ -1934,12 +1933,8 @@ compare_by_pieces (rtx arg0, rtx arg1, unsigned HOST_WIDE_INT len,
 
   data.run ();
 
-  emit_move_insn (target, const0_rtx);
-  emit_jump (end_label);
-  emit_barrier ();
-  emit_label (fail_label);
-  emit_move_insn (target, const1_rtx);
-  emit_label (end_label);
+  /* Allow the backend to override the default implementation.  */
+  targetm.finish_compare_by_pieces (target, fail_label);
 
   return target;
 }
diff --git a/gcc/target.def b/gcc/target.def
index 7d68429..0593917 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -3749,6 +3749,20 @@ negative number from this hook.",
  default_compare_by_pieces_branch_ratio)
 
 DEFHOOK
+(finish_compare_by_pieces,
+ "Allow targets with a zero flag and suitable setcc instruction to provide\n\
+an alternate implementation for @code{compare_by_pieces}.  The function\n\
+@code{compare_by_pieces} generates a sequence of equality tests that\n\
+branch to @var{failure_label} on mismatches, and fall through on success.\n\
+By default, this hook assigns @code{const1_rtx} to @var{target} in the\n\
+current basic block and @code{const0_rtx} to @var{target} in a new\n\
+@var{fail_label} basic block.  Targets like x86 can take advantage\n\
+of the property that the condition codes/zero flag are appropriately\n\
+set to avoid introducing a new basic block.",
+  void, (rtx target, rtx_code_label *fail_label),
+  default_finish_compare_by_pieces)
+
+DEFHOOK
 (slow_unaligned_access,
  "This hook returns true if memory accesses described by the\n\
 @var{mode} and @var{alignment} parameters have a cost many times greater\n\
diff --git a/gcc/targhooks.cc b/gcc/targhooks.cc
index e190369..767fe38 100644
--- a/gcc/targhooks.cc
+++ b/gcc/targhooks.cc
@@ -2094,6 +2094,24 @@ default_compare_by_pieces_branch_ratio (machine_mode)
   return 1;
 }
 
+/* This hook allows the backend to modify/override code generation for
+   compare_by_pieces.  Targets with a zero flag and a suitable setcc
+   function can use them instead of the default "compare ? 0 : 1"
+   implementation below.  TARGET is the integral mode result and
+   FAIL_LABEL is the destination for comparison mismatches.  */
+
+void
+default_finish_compare_by_pieces (rtx target, rtx_code_label *fail_label)
+{
+  rtx_code_label *end_label = gen_label_rtx ();
+  emit_move_insn (target, const0_rtx);
+  emit_jump (end_label);
+  emit_barrier ();
+  emit_label (fail_label);
+  emit_move_insn (target, const1_rtx);
+  emit_label (end_label);
+}
+
 /* Write PATCH_AREA_SIZE NOPs into the asm outfile FILE around a function
    entry.  If RECORD_P is true and the target supports named sections,
    the location of the NOPs will be recorded in a special object section
diff --git a/gcc/targhooks.h b/gcc/targhooks.h
index 1a0db8d..b99fff6 100644
--- a/gcc/targhooks.h
+++ b/gcc/targhooks.h
@@ -237,6 +237,7 @@ extern bool default_use_by_pieces_infrastructure_p (unsigned HOST_WIDE_INT,
 						    enum by_pieces_operation,
 						    bool);
 extern int default_compare_by_pieces_branch_ratio (machine_mode);
+extern void default_finish_compare_by_pieces (rtx, rtx_code_label *);
 
 extern void default_print_patchable_function_entry (FILE *,
 						    unsigned HOST_WIDE_INT,
diff --git a/gcc/testsuite/gcc.target/i386/pieces-memcmp-1.c b/gcc/testsuite/gcc.target/i386/pieces-memcmp-1.c
new file mode 100644
index 0000000..de1d82f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pieces-memcmp-1.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int foo(char *a)
+{
+    static const char t[] = "0123456789012345678901234567890";
+    return __builtin_memcmp(a, &t[0], sizeof(t)) == 0;
+}
+
+/* { dg-final { scan-assembler-not "xorl\[ \\t]*\\\$1," } } */